Double fired vertical tube heater



Oct. 10, 1961 J. w. THROCKMORTON ETAL 3,003,481

DOUBLE FIRED VERTICAL TUBE HEATER Filed June 17, 1960 2 Sheets-Sheet 1 ATTOZA/E) Oct- 10, 1961 J. w. THROCKMORTON ETAL 3,003,481

DOUBLE FIRED VERTICAL TUBE HEATER Filed June 17, 1960 2 Sheets-Sheet 2 INVENTORS JOHN M Ze wc/WMm/v 3, Ja/m/ f. 14 440;

United States Patent 3,003,481 DOUBLE FIRED VERTICAL TUBE HEATER John W. Throckniorton and John S. Wallis, New York, N.Y., assignors to Yuba Consolidated Industries, Inc, San Francisco, Calif., a corp-oration of Delaware Filed June 17, 1960, Ser. No. 36,792 7 Claims. (Cl. 122-356) This invention relates to a heater of the vertical tube type which is particularly well adapted for use in oil heating processes.

One object is to provide a heater of this type which has certain definite advantages over the heater shown in our Patent 2,818,838, issued January 7, 1958.

The heater shown and described in the aforesaid patent has a single cylindrical bank of vertical tubes mounted concentrically within a cylindrical furnace chamber which has a refractory lining on its inner wall, the vertical tubes being close to but spaced from the wall. One or more centrally located burners at the bottom of the heater discharge flame and hot gases vertically upward within the cylindrical tube bank and supply heat thereto largely by radiation. This central flame also imparts radiant heat to the refractory lining of the furnace which is exposed between the tubes. Thus the tubes are heated not only from the central flame within the tube bank but also by reradiation from the refractory lining.

The heater of our present invention also has a single cylindrical bank of vertical tubes, but the furnace is larger in diameter relative to the tube bank so that a relatively large annular space is provided within the furnace chamber between the Wall and the cylindrical tube bank.

One or more burners mounted at the bottom of the heater project flame and hot gases upwardly within the cylindrical tube bank. There are also a large number of burners of a difierent type which spread flames along the wall of the furnace chamber, the arrangement being such that the inner wall of the furnace chamber is practically covered by flames from the burners, but the flames do not project radially inward and thus avoid impinging against the outer surfaces of the tubes. Various additional advantages will appear from the detailed descri tion which follows:

' Referring to the drawings:

FIGURE 1 is a sectional elevation of a furnace which embodies our invention.

, FIG. 2 is a sectional plan view on the line 2-2 of FIG. 1, which illustrates the arrangement of the preheater or economizer tubes.

FIG. 3 is a partially sectional plan view taken on the line 3-3 of FIG. 1, which shows the arrangement of interconnecting jumpers near the bottom of the heater.

FIG. 4 is a diagrammatic view illustrating the interconnection of the tubes which is brought about by the jumpers located near the bottom of the furnace chamber outside of the tube bank.

The heater illustrated comprises a cylindrical steel wall 10, a bottom plate 11, a top plate 12 having a central opening, an auxiliary or economizer chamber 13 which may be cylindrical but is preferably square or rectangular in shape, and a stack 14 extending upwardly from. the top of the economizer chamber 13.

A single cylindrical bank 15 of vertical tubes is arranged in ten passes of four tubes each, as explained in relation to FIG. 4. Twenty of the forty tubes have the usual return bends 16 at the top and are hung in pairs from the top plate 12 by hangers 17. The tubes of bank 15 are interconnected at the bottom by a plurality of jumpers 18 and are held in position by tie bolts 19 which are attached to the bottom plate 11.

As clearly indicated in FIG. 1, the cylindrical tube "ice bank 15 is substantially smaller in diameter than the furnace chamber 10 so that the tubes are spaced from the inner Wall of the furnace chamber a distance which approximates one-fourth of the diameter of the cylindrical furnace wall.

One or more upshot burners 20 are mounted in the bottom plate 11 of the heater, and in a very large heater eight burners arranged in a circle may be employed as shown in FIG. 3.

These burners project extremely hot flame and combustion gases vertically upward centrally Within the cylindrical tube bank 15. A large number or relatively low pressure burners are mounted in the cylindrical wall 10, as shown in FIG. 3, and to illustrate their wide distribution, sixteen such burners are shown in a circular arrangement equally spaced from one another around the circumference of the chamber near the top, and similar circles of burners are disposed preferably at equal spaces below the first circle, as illustrated in FIG. 1.

Refractory material is mounted on bottom plate 11 and covers the entire inside of the cylindrical wall 10 between the burners 25. A refractory throat 26 covers the top of the heater and the inner wall of cylinder 27 which connects the top plate 12 with the economizer section 13.

The inner wall of the economizer is also provided with a refractory lining. A plurality of cross beams 30, one of which is shown in FIG. 1, are fastened to the wall 13 at their ends and constitute supports for a plurality of preheating coil banks 32, each such bank being supported by suspendcr rods 33 from its beam 34 The oil or other fluid to be heated is introduced through inlet pipe '40 and manifold 41 to which the inlet end of each individual coil 32 is connected, as shown in FIGS. 1 and 2.

Thus the economizer chamber is practically filled with the preheater coils which are closely spaced one'from another and absorb heat largely by convection from the upwardly flowing hot gases which pass from the center of the main furnace through the throat and around and over the tubes which make up the economizer coils. Thence the relatively cool exhaust gases, from which the heat has been largely extracted, pass upwardly into the stack 14.

In the arrangement illustrated there are ten coils 32, and the outlet of each is'led through inlet connecting pipe 45 and into the top of one of the tubes 15.

From an examination of the diagram of FIG. 4 it is clear that the inlet connecting pipes 45 are connected to ten adjacent tubes 15 on one side of the heater at the top. The oil or other fluid to be heated passes downwardly through these tubes in multiple, and thence at the lower end through jumpers which interconnect the tubes at the bottom. For example, inlet connector 45a joins tube 15a at the top, goes down through tube 15;: and thence through jumper 50a to the bottom of tube 15a, thence upwardly through this tube, through return bend 16a, down through tube 15a", thence through jumper Slla to the bottom of tube 15a, thence the oil flows upwardly through said tube and through an outlet connection to outlet manifold 61. Similarly oil flows from 3 groups are connected in a similar fashion to outlet manifold 62.

While the jumpers are shown diagrammatically in FIG. 4 as if they were within the cylindrical tube bank at the bottom, they are located at the bottom of the heater outside of the cylindrical tube bank 15, as clearly shown in FIG. 3.

The annular space between the cylindrical tube bank and the cylindrical wall of the heater is such that there is ample room for the jumpers below the lowest row of sidewall heaters 25.

Thus the jumpers are economically disposed, do not need any insulation as they are within the furnace and are not in danger of being damaged by overheating, since they are below the lowest circle of wall burners and are outside of the cylindrical tube bank at the bottom.

Fuel feed lines 65 connects the wall burners in each of the circles and each such line is provided with separate control valves 70 so as to readily enable the operator of the heater to adjust the wall burners from top to bottom and increase or decrease the amount of heat supplied at one end or the other of the heater.

In fact, the individual heaters are preferably provided with separate control valves 75 so that the temperature can be adjusted circumferentially in any one or all of the circular groups of wall burners. In this way, for example, all of the tubes to which the oil is directly supplied may be supplied with more intense heat from adjacent wall burners than is supplied to the tubes which are connected directly to the outlet manifolds. This gives a greater flexibility of control of the heater than is possible in heaters of a similar type which are not provided with individually controlled wall burners.

Nevertheless, the heater of this invention retains the primary advantages of the vertical tube heater having a very hot central flame passing upwardly within the cylindrical tube bank to which heat is imparted largely by radiation.

The heater may be modified in various details without departing from the spirit of our invention, and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A furnace for heat transfer at high temperature comprising an upright cylindrical furnace shell having a refractory lining, a cylindrical bank of vertical tubes having a diameter substantially one-half of the diameter of the shell, a bottom plate, a plurality of high pressure burners arranged in a circle within the lower end of the cylindrical bank and discharging axially upward to form a central column of flame and hot gases, an auxiliary furnace chamber of diameter slightly less than the cylindrical tube bank and concentric therewith at the top of the furnace, an annular throat closing the main furnace chamber except at the center where it opens into the auxiliary furnace chamber, an economizer having a plurality of coils connected to a single header at the top and forming a nest of tubes closely filling the auxiliary furnace chamber but permitting the passage of hot gases from the furnace therethrough, and a plurality of low pressure burners distributed over the entire shell of the furnace and arranged to spread flame over substantially the whole interior refractory wall of the furnace without impinging upon the adjacent outer surfaces of the tubes in the cylindrical bank, the furnace structure being such that the central column of flame and hot gases is unobstructed prior to its impingement upon the economizer coils in the auxiliary furnace chamber, the tubes of said cylindrical bank being subdivided into a plurality of arcuate coils, all of the inlet tubes of said arcuate coils being arranged side by side at one side of the furnace and connected at the top to the respective coils of the economizer, all of the outlet tubes of said arcuate coils'being arranged side by side at the opposite sides of the furnace and jumpers disposed near the bottom of the heater in the annular space between the tube bank and the cylindrical furnace wall and connecting the inlet tubes and the outlet tubes at the bottom of the furnace to the respective ends of the arcuate coils of the heater.

2. A furnace for heat transfer at high temperature comprising an upright cylindrical furnace shell, a cylin drical bank of vertical tubes having a diameter substantially less than the diameter of the shell, a bottom plate, a plurality of high pressure burners arranged in a circle within the lower end of the cylindrical bank and discharging axially upward to form a central column of flame and hot gases, an auxiliary furnace chamber sub stantially the same size in cross section as the cylindrical tube bank and concentric therewith at the top of the furnace, an annular throat closing the main furnace chamber except at the center where it opens into the auxiliary furnace chamber, an economizer comprising an inlet manifold, a plurality of indvidual coils parallel to each other and all connected at one end to the inlet manifold and constituting a nest of tubes closely filling the auxiliary furnace chamber but permitting the passage of hot gases from the furnace therethrough, a plurality of relatively low pressure burners arranged to spread flame over substantially the whole interior refractory wall of the furnace without impinging upon the adjacent outer surfaces of the tubes in the cylindrical bank, the furnace structure being such that the central column of flame and hot gases imparts radiant heat to the tubes of the cylindrical bank and is unobstructed prior to the impingement upon the economizer tubes in the auxiliary furnace chamber, the tubes of said cylindrical bank comprising arcuate coils equal in number to the individual economizer coils, having all of its inlet tubes located side by side at one side of the furnace and connected at the top to the respective economizer coils and all of its outlet tubes located side by side at the opposite side of the furnace and at least one outlet manifold to which said outlet tubes are connected at the top of the furnace, and jumpers disposed near the bottom of the heater in the annular space between the tube bank and the cylindrical furnace wall and connecting the inlet and outlet tubes at the bottom to the respective ends of the arcuate coils of the heater.

3. The structure of claim 1 in which the cylindrical tube bank is composed of ten inlet tubes at one side of the furnace and ten outlet tubes at the opposite side of the furnace and in which there are ten economizer coils connected to the respective inlet tubes.

4. The structure of claim 1 in which each arcuate coil'consists of one inlet, one outlet and two intermediate tubes, two intermediate tubes are connected in each pass between one outlet and one inlet tube.

5. The structure of claim 2 in which the jumpers are isposed near the bottom of the heater between the tube bank and the cylindrical furnace wall and interconnect the four tubes in each pass.

6. The structure of claim 1 in which fuel supply means interconnect the low pressure burners in parallel circles and an independent control valve for each circle whereby the heat applied by the wall burners may be adjusted from top to bottom of the furnace.

7. The structure of claim 1 in which fuel supply means is provided for each wall burner and an independent control valve for each burner whereby the heat applied to the furnace may be adjusted laterally between the inlet and outlet tubes of the heating coil.

References Cited in the file of this patent UNITED STATES PATENTS 1,989,612 De Florez Jan. 29, 1935 2,276,528 Throckmorton et a1. Mar. 17, 1942 2,818,838 Throckmorton et al. Jan. 7, 1958 

